Online Astronomical Distance Converter
The astronomical unit converter easily transforms cosmic distances between kilometers, astronomical units (AU), light-years, and parsecs. Ideal for astronomy students and physics calculations.
Astronomical Distance Converter
Instant conversion between Astronomical Units (AU), light-years, parsecs, kilometers, and cosmic scales
Light from the Sun takes roughly 8.3 minutes to reach Earth. Light from Proxima Centauri takes over 4.2 years!
Converted to All Units
How to use
- Enter distance magnitude.
- Select the source unit of distance (km, AU, ly, pc).
- Choose desired target unit or view conversion across all astronomical scales.
Standard Astronomical Constants
1 astronomical unit (AU) ≈ 149,597,870.7 km.
1 light-year (ly) ≈ 63,241 AU ≈ 9.461 × 10¹² km.
1 parsec (pc) ≈ 3.26 light-years ≈ 206,265 AU ≈ 3.086 × 10¹³ km.
Calculation Methodology
Conversions comply with IAU standards. 1 AU is defined exactly as 149,597,870,700 meters. A light-year is the distance traversed by light in vacuum during one Julian year, and a parsec is based on a stellar parallax angle of 1 arcsecond.
Frequently Asked Questions
What is an Astronomical Unit (AU)?
The average distance from the Earth to the Sun, standardized as exactly 149,597,870,700 meters.
What is a light-year?
The total distance traveled by a beam of light in vacuum during one year (approx. 9.46 trillion km).
What is a parsec?
A parallax of one arcsecond: the distance to an object with a stellar parallax angle of 1 second (≈ 3.26 light-years).
Which is larger: a light-year or a parsec?
A parsec is significantly larger, equal to roughly 3.26 light-years.
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